关键词: 活动地块, 活动边界带, 强震活动, 地震活动参数a,b值

Abstract: Based on the research and the division of the active tectonic blocks and their boundaries in Chinese mainland, the feature of the large earthquake activities in the 24 boundaries between the 6 grade Ⅰactive tectonic block regions and the 22 grade Ⅱ active tectonic blocks are studied. The seismicity levels on the active tectonic block boundaries are discussed considering the large earthquake frequency and the released strain energy in unit distance and time. And then, the theoretic maximal magnitude and the recurrence period of each boundary are calculated from the G-R relation. By comparing with the actual earthquake records, it is found that the intensities of the earthquake deduced from the seismic activity parameter (a/b) in the main active boundaries in Chinese mainland are consistent with that of the nature earthquakes. Meanwhile, an inverse relation is found between the recurrence period of large earthquake and the tectonic motion rate on the boundaries. These results show that the a, b value of each boundary obtained in this paper is valuable. In addition, the present seismic activities and hazards of these boundaries are also probed into with the historical data and their elapsed time on each boundary based on the hypothesis that the large earthquakes satisfy Poisson distribution.

Key words: active tectonic block, active tectonic boundary, large earthquake activity, seismic activity parameter a and b value